Through social contacts he became friendly with members of a major drug trafficking "family" that came originally from west Dublin but was more recently based in counties Kildare and Meath.

He earned their trust and became a key player in organising the logistics for substantial drug shipments being imported from mainland Europe and South America.

The plans he had laid out for the consignment, which was to become the biggest ever cocaine seizure on land, were carefully prepared.

ALIAS

And, as usual, he went to extreme lengths to distance himself from the operation. He adopted an alias in correspondence with legitimate companies as he set about organising containers, and used a safe house which had no connection with him.

But despite his involvement with previous shipments, his experience as a businessman, and his third-level education at Trinity College, Hopkins made a crucial slip-up, which allowed the garda national drugs unit to finally discover his true identity.

In his efforts to ensure that his false name would not be challenged, he supplied his real details, including his PPS number, when filling in the necessary forms for shipment.

Until then, Hopkins had not been known to gardai and, as the Irish Independent revealed last year, he had been dubbed "Mr Clean" because he did not feature in any criminal or intelligence records.

Establishing his identity was a real breakthrough for the gardai and the worldwide operation, codenamed Agon, in which they became involved as far back as December 2010 to intercept the shipments.

Despite the progress the unit made in the following 15 months, gardai are quick to point out that their ultimate success in seizing the shipment last June was heavily dependant on the co-operation they received from a Dutch law enforcement group, known as the Harc team and the Drug Enforcement Administration in the US.

The shipment originated in South America, and was tracked as it was taken across Europe by an unsuspecting transport company into Rotterdam, before it was landed at Dublin Port concealed in a consignment of wooden planks.

The street value of the cocaine was estimated to be €29.6m.

But because of its high-purity content, gardai are satisfied it could have been mixed at least four times before being sold, bringing the value to at least €120m.

The size of the shipment – 423kg – suggested some of it was likely to have been moved out of the country again, probably to markets in the UK.

Gardai are satisfied that, as well as the Kildare-Meath organisers, several drug- trafficking gangs operating here and investors from the UK and possibly mainland Europe took a huge financial hit, with the overall loss reckoned to be at least €3m.

But they say there is no evidence to link the haul financially to the Dublin criminal who left here as a result of the garda shake-down of gangland in the wake of the murder of journalist Veronica Guerin, in the late 1990s, and moved to Amsterdam, where he is still based.

Gardai have also ruled out suggestions that another criminal mastermind, Christy Kinahan, was connected to the importation.